of_pci.c

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#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/of_pci.h>
#include <asm/prom.h>

static inline int __of_pci_pci_compare(struct device_node *node,
                       unsigned int devfn)
{
    unsigned int size;
    const __be32 *reg = of_get_property(node, "reg", &size);

    if (!reg || size < 5 * sizeof(__be32))
        return 0;
    return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
}

struct device_node *of_pci_find_child_device(struct device_node *parent,
                         unsigned int devfn)
{
    struct device_node *node, *node2;

    for_each_child_of_node(parent, node) {
        if (__of_pci_pci_compare(node, devfn))
            return node;
        /*
         * Some OFs create a parent node "multifunc-device" as
         * a fake root for all functions of a multi-function
         * device we go down them as well.
         */
        if (!strcmp(node->name, "multifunc-device")) {
            for_each_child_of_node(node, node2) {
                if (__of_pci_pci_compare(node2, devfn)) {
                    of_node_put(node);
                    return node2;
                }
            }
        }
    }
    return NULL;
}
EXPORT_SYMBOL_GPL(of_pci_find_child_device);